This invention relates to a method and apparatus for removing liners from metal closures.
Metal closures having plastic liners contained therein have become increasingly popular for sealing and containing a product in a container, particularly soft drinks and beer. Typically, the closure is made of aluminum and is adapted to threadably engage with a bottle. The liner, typically, is made of a plastic material such as polyvinyl chloride or ethylene vinyl acetate.
In the manufacture of such closures a certain amount of closures are manufactured that are defective for one reason or another and thus become scrap. With the relatively recent emphasis on recycling of aluminum scrap, these defective closures have become a potentially valuable source for recoverable and recyclable aluminum scrap.
An even greater potential source for recoverable and recyclable aluminum scrap is the used closure removed from the bottle by the consumer. In order to reduce litter, a number of states have enacted legislation which requires a deposit on the container at the time of purchase whether the container is reusable or not. At least one state has carried this concept further by requiring that the closure be returned with the container for refund of the deposit. Even in those states that do not require return of the closure, it has been observed that many consumers return the closure with the empty container.
Typically, the liner is firmly affixed to the closure by an adhesive or by partially melting a portion of the liner adjacent the end wall of the closure, thus making it difficult to remove the liner. This has a severe adverse effect upon the value of the closure as recyclable scrap because the weight of the liner is approximately 33% of the total weight of the closure and thus it creates a substantial contamination problem when remelting the combination. The difference in value in today's scrap market, for example, is approximately $0.18/# for closures having the liners contained therein as opposed to approximately $0.48/# if the liners were removed.
Since a goodly number of containers are now being returned by the consumer to recover a deposit and since many of those containers are returned with the used closure attached thereto, the closure must be removed if the container is of a reusable variety. A wide variety of devices have been developed to remove closures from bottles, such as U.S. Pat. No. 3,803,795, for example, but because of the relatively low scrap value of a closure having a liner contained therein, the closures are often simply discarded.
Heretofore attempts have been made to remove the liners by burning or dissolving them in a chemical solvent to take advantage of the enhanced scrap value, but such methods have not been practically or commercially feasible. As a consequence, bottlers or others concerned with disposing of the scrap closures have not been economically motivated to introduce the scrap closures into the recyclable metal stream, and a potentially valuable asset is being lost.
It is desirable, therefore, to provide a method and apparatus for economically removing a plastic liner from a scrap metal closure to enhance the value of the closure and encourage the recovery of a valuable recyclable metal asset.